The invention relates to a power connection device for a working machine and a working machine comprising a power connection device.
The invention can be applied on different types of working machine having an undercarriage and a superstructure being pivotable relative to each other; in particular the invention can be applied on an excavator,
A working machine is usually provided with a bucket, container or other type of implement for digging, lifting, carrying and/or transporting a load,
For example, an excavator has a lift arm unit for raising and lowering an implement, such as a bucket. The excavator may have an undercarriage and a superstructure arranged on the undercarriage which superstructure can be pivoted relative the undercarriage. The lift arm is arranged on the superstructure and thereby loading and unloading the bucket can be performed at different positions by pivoting the superstructure. In addition, an excavator that is provided with wheels or caterpillar tracks is mobile.
For such an excavator, that has to be powered from an external power source during operation such as an electrically driven excavator, where an electric power cable is connected to the excavator by means of a power connection device, the movement of the excavator and/or pivoting of the superstructure relative to the undercarriage may be limited and there is also a risk of damaging the electric power cable when operating the excavator.
It is desirable to provide a power connection device, by which device the operational flexibility of a working machine can be improved.
The invention, according to an aspect thereof, is based on the insight that by the provision of a power connection device having a first power conductor member which is adapted to be pivotally arranged relative to the undercarriage and the superstructure about the substantially vertical pivot axis, it is possible to rotate the superstructure or the entire working machine while having a power cable extending in one and the same direction from an external power source to the same position of the working machine.
This in turn will increase the operational flexibility and secure a safe connection to the power source, and reduce the risk of damaging the power cable during operation of the working machine.
By “external power source” is meant a power source arranged outside the working machine at a distance from the working machine, which power source does not move together with the movement of the working machine. For example, the external power source can be a stationary electric power source where there is a need of transmitting electric energy from the power source to the working machine by means of an electric cable and a power connection means so as to power the working machine.
In one embodiment of the power connection device according to the invention, the first power conductor member is adapted to have a pivot range of approximately 360°, and preferably a pivot range exceeding 360°, i.e. the conductor member can be freely rotated relative to the undercarriage and the superstructure. This will further increase the operational flexibility.
According to a second aspect, the invention relates to a working machine. All features described herein with respect to the power connection device can be applied to the working machine according, to an aspect of the invention.
According to a third aspect, the invention relates to a system comprising a working machine according to the invention and an external power source for transmitting electric energy to the working machine.
Effects and advantages of the second and third aspects of the present invention are largely analogous to those described above in relation to the first aspect of the present invention.
Further advantages and advantageous features of the invention are disclosed in the following description and in the dependent claims.